Incendiary bullet



April 9, 1946'.

L. D. cHRlsTn-z INCENDIARY BULLETv Filed May l, 194-2 Patented pr.-9,1946 INCENDIARY BULLET .Lewis D. Christie, Bridgeport, Conn., assignorto Remington Arms Company, Inc., Bridgeport, Conn., a corporation ofDelaware Application May 1, 1942, Serial No. 441,266 I 2 Claims. (Cl.102-90) This invention relates to ammunition and particularly to thattype of incendiary bullet, of machine gun caliber, adapted to penetratethe fuel tanks of an airplane and to ignite the gasoline.

The requisites-of an incendiary bullet suitable for this express purposeare exacting. When such bullets are red from the preferred position ofattack, that is to say, on the enemys tail, the bullet must penetratethe wing structure including the flap surfaces, flap web, rear spar weband possibly other structural members, before reaching the gasolinetanks. Hence, to be effective, it is essential that the sensitivity ofthe bullet to impact be Within a relatively limited range so that themaximum flame will develop at the moment the bullet enters the gasolinetank. Furthermore, it is desirable that such bullets shall performconsistently.

Incendiary bullets of this general type are shown in a co-pendingapplication, Serial Number 439,522, led April 18, 1942, which disclosesa bullet comprising a jacket having a hollow nose portion, an aperturedcore, an incendiary composition lling both the hollow nose of the jacketand aperture of the core and a suitable heel closure. It is an object ofthis invention to provide an improved incendiary projectile` constructedand arranged to produce a maximum flame within a predetermined distanceafter striking the target. A further object is to provide a jacketedincendiary projectile having ignition means in thenose thereof forpositively igniting the incendiary composition at'the moment of impact.The ,invention likewise contemplates other im provenients in theconstruction of such bullets which will hereinafter be more fullyapparent.

In the drawing:

Fig.` 1 is a sectional view of an incendiary projectile embodying theinvention.

Fig. 2 Vis an enlarged sectional view of the bulwall thinned adjacentthe nose portion II, and

terminating in a solid body of metal at the tip I2. The jacket isprovided with a core I3 consisting of a hard metal such as steel or asuitable hard alloy, having an aperture I4. The core is shorter than thejacket so as to leave a space both in the nose portion and heel portionof the jacket. The space in the heel portion of the jacket is providedfor a suitable heel closure which, for example, may consistsimply of alead disc or the combination of a lead disc I5 and a steel disc I6, asshown in Fig. 1, held in position by crimping or turning over the end ofthe jacket as at I1. The heel closure may also include' an inertpowdered material suchas lead or amixture of lead and iron oxide asindicated at I8, which is pressed into the heel end of, the coreaperture I4 to prevent set-back. of the incendiary composition and toeffect or assist in sealing the incendiary composition I9 againstexposurev t0 the powder flame.

TheA aperture I4 ,or the core is suhstantiallir filled with anincendiary composition I9, such as a mixture of powdered magnesiumaluminum alloy and barium nitrate in substantially equal proportions.This composition is preferably loaded into the core aperture in two ormore increments, the relative size of the increments being susceptibleto considerable variation. In accordance with a preferred procedure twoincrements of charge are used, the first being somewhat larger than thesecond. Each increment is subjected to a pressurewhich preferably is notless than about 7000 pounds persquare inch,

and may be as high as about 28,000 pounds per' square inch. Although theparticular loading technique described has been found to effect verysatisfactory performance it will be understood that variations thereofmaybe made within the scope of the invention. A

Referring to Fig. 1, the end of the core adjacent the nose portion ofthe jacket is provided with a counterbore 20 concentric with the coreaperture I4 and adapted to receive a cup or capsule arranged to containa percussion `sensitive priming composition. Any one of many well knownpowder igniting ammunition priming com positions may be used. A very`convenient cup or container is astandard .22 caliber cartridge case 2|.The latter is supported within the hollow nose portion of the jacket byits open end 22, see Fig. 2, which is seated on the shoulder 23 of thecounterbore 20. 'Ihe .22 caliber case is of the rimre type and has asuitable primer composition 21 in its rim 24. The depth of thecounterbore may be such that the rim of the case will project forward'into the hollow nose tion ignites the incendiary composition.

portion of the jacket so as to be adjacent the wall at its thinnedportion II and immediately opposite the solid metal tip l2. It will beevident that the .22 caliber case forms, in effect, a closure for theend of the core aperture I4 and consequently when the bullet is chargedthe incendiary composition I9 substantially lls both the primed case andthe aperture of the core. When the bullet is being charged with theincendiary composition it is quite likely that the charging pressureswill move the primed case slightly off of the shoulder 23 towards thenose..

of the jacket but such displacement will not be suflicient to free theopen end 22 of the casefrom the core aperture. Y

A substantial improvement in the certainty and uniformity of ignition ofthe incendiary composis loaded the cartridge case. During this processthe nose of the bullet is subjected to great pressure which issuiiicient under abnormal conditions to deform the jacket. Hence, if therim of the primed case were to be positively held in close proximity tothe thinned wall portion of the jacket the deformation of the wall mightignite the priming composition. However, by providing the end of thecore with a relatively deep counterbore 25 the case will be supported inthe position 'shown by the dotted lines, in Fig. 3 only by the compactedincendiary composition and in the event that the nose of the jacket isdeformed the fpriined case issubstantially free to move away tion iseffected by the use of such a housed prim-'V'v ing composition, whichappears to function as follows: When the bullet strikes the target theforce of impact causes the wall of the jacket at its thinner portion I Ito collapse, as shown in Fig. 2, whereby the solid metal tip I2telescopes rearwardly engaging the head of the primed case and forcingthe case towards and into the core. r)The walls of the vcase arecrumpled, and therim -24 of the -case is driven against the end 26 ofthe core. The rim is then pinched between the end 26 of the core and thesolid metal tip I2 of the bullet whereby the priming composition in `therim is ignited and the ame, heat and pressure of its combus- The primedcase thus constitutesfignition means responsive to the force of impactto positively' set re to the incendiary composition. Bullets formed inaccordance with this invention have been Vfound to ignite immediately onstriking the target and to acquire a maximum ame at a pointcorresponding approximately to the location of an airplane gas tankwithV respect to its usual covering. v

A modification of the bullet is shown in Fig. 3. In this form thecounterbore 25 is made of such depth that the .22 caliber case may beassembled charging pressures are suicient to force the primed case upinto the hollow nose of the jacket as indicated by the dotted lines.

As in the former case when the bullet strikes the Vtarget the case isforced into the counterbore until the rim of the case is pinched betweenVthe end 26 of the core and bullet tip I2, thereby igniting the primercomposition and the incendiary composition. In this instance the primedcase is partially supported by the compacted incendiary composition inthe core and case but ap-V parently the incendiary composition issufficiently displaced and compressed by the blow to permit the rim ofthe case to seat on the end 2G of the core as shown in Fig. 4.

This form of the invention is particularly adapted to insure safety whenthe bullet is being rom .the deformation, thus obviating any likelihoodof premature ignition of the priming composition. -It Vwill beunderstood that the length and contour of the core can be varied toeffect any -`desired relationship between the core end, the primed shelland the jacket. Y

Although the use of a .22 caliber case has been shown and described itwill be understood that any other priming mixture container may be used,Vand other variations and modifications made within the scope of theappended claims, which claims are to Vbe broadly construed.

W hatis claimed is:

l. An incendiary bullet Comprising a jacket having a body portion and anintegral nose portion, said nose portion comprising a solid metal tipjoined to said body portion by an area of minimum cross section in saidjacket nose; a one-piece core substantially -lling the body portion ofsaid jacket and leaving a hollow nose, said core having an axialaperture extending therethrough; ignition means closing one end of saidaperture comprising a primed cartridge case supported within said coreaperture and extending into the hollow nose portion of said jacket; anannular recessed shoulder in the `front cf said core constructed andarranged to form a support for the open end Aof said primed cartridgeand 'to locate the rim of 'said primed cartridge in proximity to vthethinned area of said nose; and an incendiary composition iillin'g boththe 'aperture of said core and said cartridge case.

2. An incendiary bullet comprising a ljacket having al bo'dy portion andan integral nose portion, said nose portion'comprisng 'a substantiallysolid tip joined 'at its base to the'body portion of said jacket by awall section 'of minimum cross section; a core piece in the body portionof said jacket, said core piece having an aperture'and spaced from thebase ofsaid tip 'to 4provide said jacket with 4asubstar'itially hollownose; 'an incendiary 'charge in the aperture of' said core; ignitionmeans for said incendiary Vcharge comprising an impact responsivedevice; and means to rigidly support said impactre'sponsive device insaid hollow nose immediately `be'r'rea'tli thebase of said solid tip and`in proximity to the -wfall -S'ction of minimum cross section whereby on.im-

pact said wall section willv collapse and enable the base of .said solid'tip to abruptly LEWIsD. CHRISTIE..

